This invention relates to magnetic disk drives, and to a new cartridge for a flexible magnetic disk.
Recently, magnetic disk drives which write and read digital data from flexible magnetic disks have been extensively used. These are frequently referred to as "floppy" disks and "floppy disk drives." These drives have been extensively used for small, so-called microcomputer, systems, for word-processing applications and the like. The flexible disk cartridge includes a relatively thin, flexible jacket which is inserted into the floppy disk drive. The disk drive clamps the flexible disk onto a motor shaft which rotates the disk which is contacted by a read/write head. This cartridge exposes certain areas of the disk recording surface to dust contamination, liquid spillage, fingerprints, and scratching. Also, the flexible jacket allows the possibility of mechanical damage to the entire disk. Examples of floppy disk drives which accept this type of flexible cartridge are shown in U.S. Pat. Nos. 3,990,111--Elliott, 3,678,481--Dalziel et al., 3,815,150--Stoddard et al., 4,125,883--Rolph, and 4,089,029--Castrodale et al. Floppy disk drives have the great advantage of ease of insertion and changing the magnetic disk cartridge so that the operator can select the disk cartridge upon which the drive is to operate. However, present day floppy disk drives are not capable of operating with the precision, high speed and reliability which is present in the rigid disk drives. Floppy disk drives usually have linear actuators with access for the actuator being provided through an opening in the cartridge. U.S. Pat. No. 4,074,330--Norton et al. shows a disk drive having a Bernoulli plate for stabilizing a flexible disk to prevent flutter and to maintain an air bearing.
Rigid disk drives, such as the IBM 3350, usually have a fixed rigid magnetic media. The magnetic heads do not contact the magnetic surface, but ride on a thin film of air. Because of this, and other features, these disk drives are capable of extremely precise and high speed operation.
High speed and precision are also achieved in minicomputer disk drives which accept rigid cartridges, or disk packs, which enclose and protect the rotating magnetic disk. In such disk packs, the magnetic disk surface is mounted on a precision rigid substrate which is rotatable inside the disk packs. These disk packs are expensive and they cannot be changed on the machine with the same ease with which the so-called "floppy" disk cartridges can be inserted and removed.
It is an object of the present invention to provide a cartridge for a flexible disk which provides ease of insertion and removal and relatively low expense, while at the same time providing good protection for the flexible disk and allowing high speed reliable performance of the disk drive.